1. Field of the Invention
This invention is directed toward an improved tree processing apparatus.
The invention is also directed toward an improved method of processing tress.
The invention is more particularly directed toward an improved tree processing apparatus of the type having a tree processing head mounted at the end of a boom which boom is mounted on a vehicle. In one embodiment of the invention, the improvement comprises providing a unique mounting for the tree processing head boom. In another embodiment of the invention the improvement comprises providing passive support means on the vehicle for the tree being processed. The tree rests both on the vechicle and the ground during most of the processing process thereby minimizing stress in the apparatus. In the preferred embodiment of the invention the unique mounting for the tree processing head is combined with the passive tree support means on the vehicle.
The invention is also more particularly directed toward an improved method of processing trees using a boom with a tree processing head at is end. In the improved method, the tree can be selectively processed full length or bucked.
2. Description of t he Prior Art
Tree processing apparatus employing a tree processing head suspended at the end of a knuckle boom is known. The tree processing heads are quite compact and usually carry tree feeling means, tree delimbing means, and tree feed means which are usually in the form of rollers. The knuckle boom positions the processing head adjacent the base of a tree to be felled. The tree is grabbed by the delimber arms, which also act as grapple arms, and while the tree is held, it is cut through with the felling means. The felled tree is then loosely held in a generally horizontal position by the delimbing arms on the processing head and the feed means are operated to feed the tree past the arms delimbing the tree.
This known apparatus is quite compact and energy efficient. It is especially suited for selective harvesting in forests, particularly in thinning operations. However the unit has some deficiencies. Usually about half the weight of the felled tree being processed is carried by the processing head while the top portion of the tree rests on the ground. A relatively strong and therefore heavy knuckle boom is required to support this weight. Also, the knuckle boom requires an additional heel boom near its outer end to help manoeuvre the vehicle in case it becomes stuck. The outer end of the knuckle boom itself cannot be used to help manoeuvre a stuck vehicle because the processing head is suspended from it. The addition of the heel boom further increases the overall weight of the apparatus making it more costly and less energy efficient.